The present invention relates to a turbine apparatus especially of low specific speed including a turbine runner and a governor for controlling a rotational speed of the turbine runner.
Generally in a turbine apparatus of low specific speed, so-called S characteristics as shown in FIGS. 1A and 1B occur, and the turbine apparatus is controlled as disclosed by JP-A-2002-303244 to be restrained from being made unstable in its operation by the S characteristics.